Reaction of 4,6-O-benzylideneglycals with benzoic acid, triphenyl-phosphine, and diethyl azodicarboxylate and of the products with sodium methoxide. X-Ray structure of 1-O-benzoyl-4,6-O-benzylidene-2-deoxy-3-O-methyl-α-D-arabino-hexopyranose, C21H22O6
Abstract
Reaction of 4,6-O-benzylidene-D-allal with benzoic acid, triphenylphosphine, and diethyl azodicarboxylate gave a mixture of 1-O-benzoyl-4,6-O-benzylidene-2,3-dideoxy-α-D-erythro-hex-2-enopyranose (3) as the major product together with its β-anomer (4) and 3-O-benzoyl-4,6-O-benzylidene-D-glucal (5). Debenzoylation led to a mixture of the 4,6-O-benzylidene-D-glucal, 4,6-O-benzylidene-2-deoxy-3-O-methyl-D-arabino- and -D-ribo-hexopyranose. The structure of the arabino-isomer (6) was established by X-ray analysis of its 1-O-benzoyl derivative. Crystals are orthorhombic, space group P212121, a= 21.789(2), b= 14.772(3), c= 5.925(2)Å. The structure was solved by direct methods and refined to R 0.095.